1. Field of the Invention
The present invention relates to an exchangeable module for an electric system and more particularly to an exchangeable module that easily and safely is replaced from the electric system.
2. Description of Related Art
The European standard “EN60950: Safety of Information Technology Equipment” stipulates protection in operator access areas in EN60950 2.1.1. EN60950 1.2.8.2 defines a primary circuit is directly connected to the AC main supply, and EN60950 1.2.8.3 defines a secondary circuit has no direct connection to a primary circuit and derives its power from a transformer, converter or equivalent isolation device, or from battery. Power supplied to a secondary circuit is provided through a transformer, a current transformer or insolating circuit. According to the standard, to protect the operator from hazards, a common safety design in operator access areas is the Safety Extra Low Voltage (SELV) circuit that has reinforced insulation from primary circuit. This device is insulation type electronic device. However the reinforced insulation is complex and is hard to design, so the cost of this device is very high. Another common safety design uses a safety interlock by a hardware device to prevent a user from directly touching the primary circuit. This device is a Primary type electronic device. Based on this, a space for reinforce insulation between the operator access area and the primary circuit is required when the operator replace the internal power. Therefore the hardware device is also very complex and hard to design.
Electronic modules used more often recently to add or extend capabilities of parent electronic devices necessitate the use of Safety of Information Technology Equipment to ensure safe operation. Many electronic devices provide convenient means to connect electronic modules. However, some electronic modules are primary circuits, and Safety of Information Technology Equipment is required in the parent electronic device to protect users. For example, an uninterruptible power supply (UPS) basically has a primary circuit and battery modules. The battery modules have a useful life and must be periodically replaced in many cases without deactivating the UPS. This necessitates replacing the battery modules when the UPS is “hot” to maintain normal operation of the equipment attached to the UPS. In general, the design of the UPS comprises one of the following features:
(1) The battery charger circuit is designed as a safety extra low voltage circuit, so as to the insulated transformer is needed.
(2) Using a battery connector with reinforced insulation between the part where the user can touch and charger circuit (a primary circuit) when replace the battery modules.
However, the first feature requires an extra power converter circuits that use a significant amount of space in the UPS and the cost is up. As for the second feature, the reinforced insulation required the connector to meet the safety requirements. Meanwhile, because all the power is come from battery when UPS operates in reverse mode, the current rating of the connector is so high. This also causes the cost to go up significantly.
With reference to FIG. 8, a conventional connector (90) to connect the battery module (70) to the circuit (80) of the UPS (60) has a socket (91) and a plug (92). The plug (92) attaches to or detaches from the socket (91) to connect or disconnect the battery module (70) and circuit (80). The user has to manually connect or disconnect the connector (90) so as to a cheap connector (90) without reinforced insulation to the operator can be very dangerous.
The present invention provides a power source connector to mitigate or obviate the aforementioned problems.